Isolation and Identification of Entomopathogenic Fungi from the Soils of Northwest Iran and their Biological Control Efficacy on the Flour Moth (Ephestia kuehniella)

Abstract

Entomopathogenic fungi have the potential to serve as alternatives to or supplements for chemical pesticides in insect biocontrol, with many of these fungi being utilized in commercial and integrated pest control practices globally. This study aimed to isolate and evaluate the efficacy of various entomopathogenic fungi for the biocontrol of the flour moth, Ephestia kuehniella (Lep: Pyralidae). Multiple isolates of entomopathogenic fungi were acquired from soils across different districts of Azerbaijan province in northwest Iran, and their virulence against E. kuehniella larvae was assessed. Seventeen isolates representing diverse entomopathogenic fungi were isolated and purified using the soil trap method from 20 distinct soil samples. Their pathogenicity against E. kuehniella was evaluated in three replicates through the immersion technique at concentrations of 104, 105, 106, 107, and 108 conidia/mL. Identification of selected fungal isolates was based on morphological features, mycological parameters, and sequencing of the internal transcribed spacer (ITS) region. The study identified seven fungal species, namely Lecanicillium lecanii, Beauveria bassiana, Metarhizium anisopliae, Purpureocillium lilacinum, Aspergillus oryzae, Penicillium citrinum, and Aspergillus lavus, among the 17 isolates collected. Bioassay assessments revealed the susceptibility of 4th-instar larvae of E. kuehniella to the selected isolates, with the larval mortality rate increasing with higher conidial concentrations. A. lavus, A. oryzae, P. citrinum, and P. lilacinum exhibited maximum virulence, causing nearly 90% lethality, while Metarhizium anisopliae demonstrated the lowest level of virulence, resulting in approximately 30% lethality in E. kuehniella. The virulence pattern of isolates across different concentrations was notably distinct. The findings of this research demonstrate that entomopathogenic fungi isolated in this investigation could be effectively incorporated into future pest management programs.